The present invention generally relates to an improved apparatus and system for attaching a belt fastener assembly to an end of a belt with rivets. The present invention is more particularly directed to such an apparatus and system which permits the rivets to be installed by use of a non-manually powered driving tool resulting in savings in labor, minimizing fatigue of rivet installers, and more consistent belt fastener attachment of high integrity.
For more than two decades, rivet systems have been available to secure belt fasteners to conveyor belting. Over this time, modest improvements have been made to such systems. Most of these improvements have been directed to the driving of single rivets or multiple rivets with manual force through the use of a hammer.
The belt fastener generally includes an upper plate for overlying one side of the belt end and a lower plate for underlying the other side of the belt end. The plates include rivet receiving apertures which are either alignable or fixedly aligned by a U-shaped connection between the plates adapted to receive a hinge pin.
Such systems generally also utilize rivet assemblies. Each rivet assembly includes a rivet having a shank, a domed head at one end of the shank, and a counter sink within the opposite end of the shank. The rivet assembly also includes a pilot nail extending from the counter sink of the rivet.
When a rivet is installed through the use of such a manual system, the first strike of the rivet assembly drives the rivet assembly through a rivet receiving aperture of the top plate. The pilot nail pierces the belt and guides the rivet into position through the aligned rivet receiving apertures of the upper and lower plates while the pilot nail is received within an anvil die aperture of an anvil die plate. The anvil die aperture fixes the pilot nail relative to the rivet such that during subsequent successive strikes with a hammer, a die forming head of the pilot nail deforms the counter sink outwardly and upwardly to clinch the counter sunk end of the rivet to the underside of the lower plate. U.S. Pat. No. 3,913,180 shows and describes such a system, which patent is incorporated herein by reference.
The force required to manually drive each rivet assembly one at a time as described above requires a hammer weighing on the order of two pounds. Between five to ten strikes with the hammer are generally required to complete the process for each rivet. Because a typical 48"-wide belt generally requires 270 rivets to be driven, up to 2,700 hammer strikes are required to complete the belt fastener attachment. This is not only fatiguing to the rivet installer, but it can also take between 45 minutes to one hour to complete an installation.
While drive tools for manually driving up to five rivet assemblies at a time have been developed, these tools require about five times the force for each strike. Hammers weighing about five pounds have been used with such tools. While much greater physical effort is therefore required with such tools, such tools do provide a small time advantage as compared to single rivet tools.
Unfortunately, in addition to the time and fatigue disadvantages of manual tools, not all manual installers generate the same striking force. In fact, the same manual installer will not generate the same driving force for each rivet assembly strike. This results in non-uniform clinching of the rivets and hence non-uniform compression of the belt along its entire width.
Alignment of the rivet assemblies with the rivet receiving apertures of the upper and lower fastener plates and the anvil die apertures is also important to assure a uniform clinch of the counter sunk end of the rivets. This provides a uniform and secure clinch of the rivet to the fastener lower plate. Unfortunately, manual installation dictates rather loose alignment tolerance resulting in rivet clinches which have less than desired integrity.
The apparatus and system of the present invention overcomes the aforementioned disadvantages of the prior art. By virtue of the present invention, belt fasteners are permitted to be attached to belts by use of a non-manually powered rivet driving tool. Such non-manually powered driving tools generate the same force for each rivet strike resulting in uniform clinching of each rivet. Further, only two rivet strikes are uniformly required to install each rivet by virtue of the present invention. This further provides rivet installation uniformity and results in less installation time. Further, by virtue of the present invention, closer alignment of the rivet assemblies to the rivet receiving apertures of the upper and lower plates and to the anvil die apertures may be achieved. This results in more consistent uniform rivet clinches of high integrity. Further, because the present invention permits a non-manually powered drive tool to be used, installation fatigue is substantially reduced. The present invention therefore substantially reduces installation cost, minimizes installer fatigue, and produces more consistent belt fastener attachment of high integrity.